The proposed Phase II study will continue the development of an innovative, immunoassay-based biosensor for the detection and quantitation of Cryptosporidium oocysts in drinking water. Current methods for detection and quantitation of this pathogen frequently are characterized as technically demanding, time-consuming and labor intense, leading to poor recoveries and false positives and false negatives. The Phase I results showed that the biosensor was capable of detecting 10 oocysts/ml in buffer at a two-fold signal-to-noise cutoff. Phase II activities will focus on improving the detection limit and developing an optimized immunoassay strip device and reader. Water samples collected from a variety of natural sources will be evaluated in the prototype detection system. The irmnunoassay itself should take less than 30 minutes to complete. The availability of more rapid, quantitative methods for detecting water-home pathogens will help to identify and manage the presence of these organisms for community water supplies, thereby minimizing the exposure of the public. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE